One of the solutions is to rename the registry key HKLM\SYSTEM\CurrentControlSet\Services\WinDefend to HKLM\SYSTEM\CurrentControlSet\Services\WinDefend-BLOCKED (for example).
To learn how, read on.
Renaming the registry key requires a restart in Safe mode
As far as I know, the registry key HKLM\SYSTEM\CurrentControlSet\Services\WinDefend cannot be renamed starting windows normally.
To start in Safe mode, press WinKey + R, type msconfig and hit Enter.
In the System Configuration window that opens, click the Boot tab, and then check Safe boot as shown in the screenshot below. Click Apply and then press WinKey + x followed by u and u to shut down. Once the computer has turned off, press the physical power button to turn it on again.
This will start your computer in Safe mode.
In Safe mode, rename the registry key
Once you have entered Safe mode, open the registry editor – press WinKey + R, type regedit and hit Enter.
Right-click the HKLM\SYSTEM\CurrentControlSet\Services\WinDefend key and rename it to WinDefend-BLOCKED.
That’s it!
All that remains is to leave the Safe mode and restart normally. Use the same procedure as before (msconfig) – but this time uncheck Safe boot before restarting.